MPL 20x3x2 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after ten years, the performance loss is only ~1% (based on calculations),
• They are very resistant to demagnetization caused by external magnetic fields,
• Because of the reflective layer of nickel, the component looks visually appealing,
• The outer field strength of the magnet shows remarkable magnetic properties,
• With the right combination of materials, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the structure),
• With the option for fine forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Wide application in modern technologies – they are used in data storage devices, electromechanical systems, healthcare devices as well as other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in compact dimensions, which makes them ideal in compact constructions

Disadvantages of rare earth magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to external force, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and increases its overall strength,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent decline in performance (depending on form). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Magnets exposed to moisture can degrade. Therefore, for outdoor applications, we advise waterproof types made of coated materials,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is restricted,
• Potential hazard from tiny pieces may arise, in case of ingestion, which is significant in the family environments. It should also be noted that minuscule fragments from these assemblies might disrupt scanning when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting force for a neodymium magnet – what it depends on?

The given lifting capacity of the magnet represents the maximum lifting force, measured in ideal conditions, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Determinants of practical lifting force of a magnet

The lifting capacity of a magnet is determined by in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet and the plate lowers the holding force.